An ontology in which things are always in process and nothing is ever fully achieved or closed is not in itself morally or politically superior to any other way of thinking. It simply solves some problems some of which are moral and political. In particular, one never has to draw a line between that which is achieved and henceforth settled, beyond dispute and universal and that which isn't.
It is an axiom of experience and so of common sense that not everything is settled, beyond dispute and universal (Parmenides notwithstanding) and so to say that there are some things like this means that there must be a line. The drawing of this line is one of the main problems of modern philosophy and seems irresolvable (as does the question of such resolution's desirability). Doing away with the line does away with the problem, which is both philosophical and political.
We could revive Parmenides but that doesn't seem very plausible or useful (this is dismissive but probably fair, particularly if we take experience as the spur of conceptualisation a la Whitehead). The opposite is plausible and can be shown to work, to generate greatly conceptually sophisticated schemas that are able to do justice to all sorts of aspects of reality while redefining what we mean by reality itself.
If this leads to moral and political sophistication too then this is excellent. Yet these are not the only problems that such conceptual work resolves nor the only problems that it is a response to.
If a term is valuable it must be a 'meso' term. Too general and it becomes meaningless, too global. Too specific and it is too inapplicable, too local. Politics is like this. When politics becomes the question that dominates any given consideration it becomes effectively meaningless because there ceases to be any way of distinguishing between different kinds of good, different valuations. It is valuationally hegemonic - and this is bad for all sorts of reasons, including political ones!
If politics is too easily achieved (if 'everything's political') then there is no reason to do anything in particular in order to achieve politics. If politics is too rare (only appearing in epochal fissures or 'events') then despondency sets in (what agency could anyone have in bringing about something that is by definition vast and impersonal?).
Politics must be accessible but not without effort: just like everything. Moreover, it shouldn't be the only kind of value as this both eliminates other kinds of valuation but also makes politics total, which also makes it meaningless (and so you've lost all kinds of values but also lost politics - worst of all worlds).
Above all politics must be an achievement and this makes process ontology fit it perfectly. The alternative, where elements of reality are absolute, unchanging and beyond dispute, means that the passing and contingent can be subordinated to this fundamentally ulterior realm. Those with access to that realm - which is always already achieved and need only be accessed - thereby become legislators, even dictators, for those who merely splash around in what is contingent. This is intolerable.
For the above reasons: Politics (as I would like to describe it) needs process but process must be justified for more than political reasons. Other valuations must be involved.
Pluralism must also mean that politics is only one value among others. This is what too many people forget.